CBP applies the GRI classification rules and relevant chapter notes. Components whose primary function is structural or aesthetic — such as door panels, exterior mirrors, or interior trim — are generally body parts or accessories. Components whose primary function is mechanical (e.g., door hinges classified as base metal articles) or electrical (e.g., power window motors) may fall under separate headings. When a component serves dual functions, the essential character or specific chapter notes govern. Binding rulings are advisable for high-volume ambiguous items.

To claim first-sale valuation — using the manufacturer-to-middleman price rather than the middleman-to-importer price — the importer must demonstrate that the first sale was clearly destined for US export and that the price was at arm's length. Required documentation typically includes the manufacturer's invoice, the middleman's invoice, proof of payment at each level, and evidence that the goods were destined for the US at the time of the first sale. CBP may request additional records; maintaining a robust paper trail from the factory level is essential.